Internal combustion piston engine



1957 KARL-HEINZ R. ebscHEL ETAL 2,803,235

INTERNAL COMBUSTION pxsrou ENGINE Filed April 20, 1955 m m e W 7 AARL-HE/MZ R. 6630/41.-

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United States Patentc) mTERNAL COMBUSTION PISTON ENGINE Karl-Heinz R. Giischel, Stuttgart-Unterturkheim, and Hans R. Griizinger, Plochingen, Germany, assignors to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Application April 20, 1955, Serial No. 502,642

Claims priority, application Germany April 22, 1954 4 Claims. (Cl. 123-140) Our invention relates to an internal combustion piston engine of the type in which the fuel is injected into the air charge sucked into the cylinder prior to and/or during the compression thereof for subsequent evaporiza tion and ignition by a spark plug.

In engines of thi type the power of the engine is controlled by a butterfly valve disposed in the air intake duct and by a vacuum-controlled fuel-injecting pump adapted to intermittently feed metered quantities of fuel into the cylinders of the engine, such quantities being controlled by the pressure prevailing in a vacuum chamher. This chamber is connected to a port located in the air intake duct inside of the butterfly valve within a zone passed over by a high speed stream of air flowing past the butterfly valve when the same approaches idling position. Therefore, any adjustment of the butterfly valve has the dual effect of altering the quantity of air sucked into the cylinder past the butterfly valve and of altering the pressure prevailing in the vacuum chamber of the fuel-injecting pump to thereby vary the quantities of fuel injected into the cylinders.

When the engine is cold the lubricating oil is more viscous and, therefore, the engine requires a higher power for satisfactory idling operation than it does at a normal operating temperature.

It i the object of our invention to provide improved means for such an automatic control of the engine that in cold condition the engine will produce a higher power for satisfactory idling operation than it does at a normal operating temperature.

Further objects of our invention will appear from a detailed description following hereinafter of two preferred embodiments of the invention illustrated in the accompanying drawings. We wish it to be understood, however, that such detailed description serves the purpose of illustrating the invention rather than that of restricting or limiting the same. In the drawings,

Fig. l is a sectional partial view of an internal combustion engine and of the associated vacuum-controlled fuel-injecting pump, and

Fig. 2 is asectional view similar to that of Fig. l on an enlarged scale showing a modification of the engine illustrated in Fig. 1.

A cylinder block having four cylinders 11 is provided with a cooling jacket 12 and with a cylinder head 13. For the admission of air to the cylinders an intake manifold is provided which communicates with intake channels, such as 14, leading to the individual cylinders 11, each channel 14 being controlled by an intake valve 15. A fuel-injecting pump 16 is geared to the engine by known means including a shaft 19. The pump 16 is adapted to intermittently feed metered quantities of fuel through pipes 17 to fuel-injecting nozzles, such as 18, mounted in the cylinder head 13 for the injection of the quantities of fuel into the cylinders 11 of the engine.

The pump 16 is provided with a vacuum chamber 21. The pressure prevailing in this chamber 21 controls the ICC 2 metering function of the pump. For this purpose, the quantities of fuel intermittently fed by the pump are ad-' justable by axial displacement of a control rod 22 guided in the block of pump 16 and connected to a diaphragm 23 which confines a chamber 21. The chamber 21 is connected by a conduit 24 including a pipe to a port 25 loshown).

The intake manifold 20 is provided with the conventional dust filter (not shown) and with a butterfly valve 27 adapted to control the air intake duct 26 to thereby determine the weight of the air charge admitted into the cylinders through the intake valves, such as 15. The pump 16 is so adjusted and operated as to cause the injection of the fuel while the valve 15 is open to admit.

the air into the cylinder where the fuel evaporizes and forms a gas mixture with the air which is compressed by the piston subsequently to the closing of valve 15 and is then ignited by a spark plug.

The port 25 is located in the wall of the intake manifold 20 inside of the butterfly valve 27 within a zone over which the stream of air flowing past the butterfly valve 27 passes at a high speed. Therefore, the pressure prevailing in the port 25 is influenced by the stream of air flowing past the edge of the butterfly valve and differs from the pressure prevailing in the channels 14.

The power developed by the engine is controlled by. the adjustment of the butterfly valve 27 which may be effected manually or automaticaly in the conventional mannerby suitable means (not shown). In Fig. 1 the butterfly valve 27 is shown in the position to which it is adjusted when the engine is idling.

For the purposes of the present invention the air conduit 24 is connected by a passageway 28, 29 to the atmosphere. In the embodiment shown, the passageway 28, 29 is constituted by bores provided in a boss 30 with which the wall of the intake manifold is provided. The bore 28 leads to the air intake duct 26 outside of the butterfly valve 27 where substantially atmospheric pres sure prevails. Another air passageway 31 bypasses the butterfly valve 27.

A valve mechanism is provided to control both the passageways 31 and 28, 29 so as to open or close the same. In the embodiment shown in Fig. 1 this valve mechanism comprises a butterfly valve 32 provided in the passageway 31 and a needle valve 33 guided for axial displacement in a plug 34 screwed into the boss 30 to plug the outer end of the bore 28. This bore is provided with a tapering internal wall constituting a valve seat cooperating with the needle valve member 33.

The cylinder head is provided with a conventional cooling jacket 35 through which a suitable cooling liquid may be circulated. The cooling jacket 35 is provided with a bore in which a thermostat element 36 is inserted having an outwardly projecting stem 37. When the engine is cold the stern assumes the position shown. When the temperature of the engine rises the stem 37 is moved in the outward direction. The boss 30 is pro vided with an eye 38 from which a pin 39 projects. A three-armed lever fulcrumed on this pin has a depending arm 40, an upright arm 41 and a horizontal arm 42. The arm 40 is connected to the stem 37 by a connecting rod 43. The arm 41 is connected by a connecting rod 3 44 to an arm 45 secured to the outer end of a shaft 46 on which the butterfly valve 32 is mounted. The horizontal arm 42 is connected to the needle valve member 33 by a connecting link 47.

From Fig. 1 it will appear that when the stem 37 is in the position shown, i. e. when the engine is cold, the butterfly valve 32 and the needle valve member 33 are both in open condition. Therefore, an additional quantity of air is admitted through the passageway 31 such as is necessary to produce the additional power required to keep the engine idling in cold condition. As the needle valve 33 is lifted from its seat in the bore 28, the absolute pressure prevailing in the conduit 24 is reduced by the admission-of air past the needle valve 33. Therefore, the diaphragm 23 confining the chamber 21 will assume a position in which more fuel will be metered out to the injection nozzle 18 than it would be the case when the valve member 33 were closed. This increased quantity of fuel is required to supply the increased air charge with fuel, such air charge being increased by the passageway 31.

When the temperature of the engine rises, the water circulating through the cooling jacket 35 will be heated and will cause the thermostat 36 to move its stem 37 outwardly whereby the needle valve member 33 will be raised towards its closed position and the butterfly valve 32 will be turned anti-clockwise. When the engine has reached its normal temperature of operation the needle valve member 33 and the butterfly valve 32 are closed. Hence, both of the passageways 28, 29 and 31 will be sealed. Therefore, for idling operation the engine will be supplied with that quantity of air only that flows past the butterfly valve 27. The quantity of fuel injected has been reduced because the pressure existing in the conduit formed by pipe 24 has been reduced on account of the elimination of the bypass through the bores 28 and 29. Hence, less air and less fuel is supplied to the engine for the idling operation to thus satisfy the requirements existing at a normal operating temperature.

The embodiment of the invention illustrated in Fig. 2 differs from that shown in Fig. l by the structure of the intake manifold. The passageway 31 bypassing the butterfly valve 27 has been omitted and a passageway 131 provided in the boss 130 of the intake manifold 120 has been substituted. Moreover, the boss is provided with a bore 48 intersecting both of the air passageway 28, 29 and 131. The bore 48 slidingly accommodates a valve member 49 provided with two peripheral grooves 50 and 51. An eye 138 integral with the boss 130 is provided with a pin 139 on which a double-armed lever is fulcrumed. The depending arm 140 of the lever is connected with the stem 37 by the connecting link 43, whereas the lever arm 141 is connected by a link 144 with the valve member 49. When the engine is cold the stem 37 assumes the position shown in Fig. 2 causing the valve member 49 to assume a position in which its peripheral grooves register with the passageways 28, 29, and 131 respectively, so as to open such passageways. When the temperature of the engine rises to a normal operating condition the double-armed lever 140, 141 is rocked in clockwise direction thereby closing both passageways 28, 29 and 131. The operation of the embodiment shown in Fig. 2 is similar to that described hereinabove with reference to Fig. l and the explanation thereof need not be repeated.

While in both of the embodiments described the thermostat 36 is so positioned as to be responsive to the temperature of the cooling liquid, the thermostat may be readily so disposed as to respond to the temperature of other parts of the engine. Also, while the fuelinjecting nozzle 18 is illustrated as injecting the fuel into the cylinder, it may be also so disposed as to inject the fuel into the air intake duct.

From the foregoing description it will appear that in our novel internal combustion piston engine a thermostat responding to the temperature of the internal combustion engine, for instance to that of the cooling medium or the like, is operative when heated to actuate two valve members thereby increasing the throttling effect, one valve member, preferably in form of a needle valve, being disposed in a secondary bypass tapping the air intake duct outside of the butterfly valve and communicating with the pressure tapping line, the other valve member being mounted in an air bypass admitting air into the air intake duct inside of the butterfly valve.

While the invention has been described in connection with several different embodiments thereof, it will be understood that it is capable of further modification, and

this application is intended to cover any variations, uses, or adaptations of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as fall within the scope of the invention or the limits of the appended claims.

What we claim is:

1. Internal combustion piston engine having an air intake duct in communication with the atmosphere, a butterfly valve therein, a vacuum-controlled fuel-injecting pump adapted to intermittently feed metered quantities of fuel controlled by the pressure in a vacuum chamher for the injection of said quantities into the cylinders of the engine, a port located in the wall of said duct inside of said butterfly valve within a zone passed over by a high speed stream of air flowing past said butterfly valve when the same approaches idling position, an air conduit connecting said port to said vacuum chamber enabling said pump to meter said fuel quantities in dependence on the position of said butterfly valve, a first air passageway also in communication with the atmosphere and connected with said duct at least behind said butterfly valve in by-passing relationship with said butterfly valve, a second air passageway connecting said air conduit to the atmosphere, a thermostat responsive to the temperature of said engine, and a valve mechanism for both of said' air passages and operatively connected to said thermostat and to said air passages to control both of said passageways so as to open the same when the temperature of said engine drops to thereby increase the quantity of air and fuel admitted when the engine is cold.

2. Internal combustion piston engine as claimed in claim 1 in which said valve mechanism comprises a butterfly valve mounted in said first air pasageway, a needle valve mounted in said second air passageway, and a linkage connecting said last-mentioned butterfly valve and said needle valve for common adjustment, said linkage being connected to said thermostat for actuation thereby.

3. Internal combustion piston engine as claimed in claim 1 in which said valve mechanism comprises a valve member, the wall of said intake duct being provided with a bore intersecting both of said air passageways and slidingly accommodating said valve member, the latter being connected to said thermostat for actuation thereby.

4. An internal combustion engine according to claim 1 wherein said first air passageway is in parallel with said air intake duct and is connected thereto ahead and behind said butterfly valve.

No references cited. 

